Fuel's Winter Project: Build It Before It Blows

[JeremyH]

It has thicker webs because it's less dense. You guys are crazy if you think a cast crank will be on par with a forged crank.

Makes perfect sense to me. Indeed they are thicker to make it stronger, one is thinner because the steel is denser. Two ways to get the same result.

Much like the whole chromoly vs steel thing. Chromoly is denser and stronger. So you can machine thinner parts with less material and get the same strength as regular steel being thicker. The end result is two similar strength parts regardless of which way its made.

The cast cranks (me, Josh, Jeremy) have all done very well with higher hp numbers. Higher to me means high 600's to mid 700's. Survived clutch dumps, many track passes, plus normal driving. Those are levels that kill GT500 motors.

What would you expect? Does it make any sense to spend $1000 on a new forged crank when the cast one will fit the bill? BTW new forged cranks are from $800 to $1100. Kellogg doesn't make them anymore. They sold the tooling to Lunati. Eagles are in the $800 range while Lunati goes for over $1000.

The biggest thing to me would be having 33% more fastening with the 8 bolt vs 6 bolt. Like I said earlier I would probably go forged with something built for big power like 1000. Still though, it would be interesting to find out.

Dillon was running 700rwhp+ on his old setup with a stock crank as well.


That other crank thread reminded me of something Bruce. The 99-01 Windsor motors had 8 bolt cast steel cranks, you could probably find one of those cheap in a junk motor. lol

 

[BruceH]

That other crank thread reminded me of something Bruce. The 99-01 Windsor motors had 8 bolt cast steel cranks, you could probably find one of those cheap in a junk motor. lol

I'm good. Have two cast cranks in the garage, one is turned, polished, and ready to go. My current motor has a Kellogg stroker crank. The crank and 8 Manley rods with arp2000 rod bolts were $575 shipped. That was a hard deal to pass up and I wasn't even looking to stroke my big bore, lol.

I've wondered about the flywheel fasteners but it hasn't hurt anything. There has never been any fastener damage when disassembling and I use the stock flywheel bolts. I think that friction does most of the holding with the bolts mostly applying the friction.

How far have you gone with your stock crank motor? Near 750rwhp iirc.

Edit: It's in your sig.

 

[JeremyH]

Yeah I have never upgraded flywheel bolts yet either. The flywheel does play a role in balance and harmonics just like the damper though. I do prefer one piece balanced flywheels I have run aluminum and billet steel ones. I think the aluminum was almost too light for my setup. Current flywheel is an act lightened steel flywheel. I figured some arp flywheel bolts wont hurt next time I'm in there and then I can always reuse them.

Yup numbers in sig, that's almost 900hp at the crank. I would be at 800rwhp+ if I hadn't run out of injector last time on the dyno.

Like I said I would expect a valve train or rod failure long before the crank would ever fail.

The 01 cobra crank I bought cost me $40 on ebay back then, should of held onto it and made some money lol.

 

[go302]

Makes perfect sense to me. Indeed they are thicker to make it stronger, one is thinner because the steel is denser. Two ways to get the same result.

Much like the whole chromoly vs steel thing. Chromoly is denser and stronger. So you can machine thinner parts with less material and get the same strength as regular steel being thicker. The end result is two similar strength parts regardless of which way its made.





Dillon was running 700rwhp+ on his old setup with a stock crank as well.


That other crank thread reminded me of something Bruce. The 99-01 Windsor motors had 8 bolt cast steel cranks, you could probably find one of those cheap in a junk motor. lol

That's not how that works and chromoly is just a specific type of "steel." But whatever, the stock crank holds just as much power as a forged peice. I'll call ford and let them know.

 

[go302]

Sorry not meaning to be a douche I'm fucked up right now lol

 

[JeremyH]

LOL! It's all good Cade.

Maybe we should all spring for forged aluminum blocks vice cast aluminum blocks too!

I will try my best to break the stock cast steel crank for you!

 

[go302]

Lol now you're really comparing apples to oranges! But, more power to you guys. If you guys can push as much power on a stock crank then that's awesome. Maybe there will be more than one fast 3v down at tx2k this year. Everyone seems to be getting pretty serious about repping the 3v

 

[BruceH]

It would be nice to have an unlimited cash supply for this kind of stuff. Do destructive testing on the cranks and see what it takes to break them. I have a stock crank I'd donate if someone has a test rig to simulate the motor forces. I suppose it could be supported on the bearings and have force applied to the rod area. That could also determine what will break first, rod, rod bolt, or crank. It would be a simple test though, it wouldn't take rpm into account or engine harmonics.

Maybe an old block, a come along, and a strain gauge?

 

[JoshK]

Well I have sold my fuel system for a return style setup, sold my turbo for a larger one, and have very little self discipline when it comes to turning up the boost. I guess this means when my find out where the limits are?

 

[Dark_horse]

Who has the best price on an ati?

ATI has a blem eBay store... Got mine for like 200 and it was bnib

 

[JoshK]

Can you tell me what store Bobby?



Missing parts today

 

[JeremyH]

Out with the old!

 

[JoshK]

Well the consensus seems to be that I am nuts, but progress continues anyway

 

[JoshK]

Just sold my ID1000 fuel injectors too.

 

[JeremyH]

You have to be a little crazy when your a hp/mod junkie. lol

 

[JoshK]

And the return fuel system will soon be on its way thanks to gmitch

 

[ZmanM3]

You got a great deal.

 

[eighty6gt]

I'm not sure why forged cranks have 8 bolts rather than 6. The bolts experience no shear forces whatsoever - if they did the flywheel is falling off. Maybe the 8 bolt cranks use smaller bolts? This might help with stress concentrations in the crankshaft end.

Here's something to look at. It appears the problem mainly lies with fatigue, makes sense. Stress risers. Your blower loads on the crankshaft snout. Thing is I think there's a lot of fat in the cast crank design, and nobody is doing 500,000 miles on these engines.


http://www.autosteel.org/~/media/Fi...LongProducts/crankshaft_executive_summary.pdf

 

[JeremyH]

I think that is indeed a factor on crank selection as well. A blower setup will obviously put more load on the crankshaft than a turbo setup.

 

[JoshK]

I also agree that side load from a blower would be much harder on the crank. I am turbo so I am not as worried as I would be if I had a 10rib belt drive on the front trying to spin a blower over 20lbs of boost.